This is to up date this post:
OMG The news just keeps on coming it:
Well after all these years of they saying it cannot be done…I have found proof I was on the right track, or that at least it can be done.
Full sized vans CAN GET 29/30MPG any highway speeds.
THAT blows all the "you cannot get a big box like a van to do 30MPG..."
GM Has TWO models of vans that do just that.
From
https://www.dieselplace.com/.../2-8-...press-vans.../
28 Expressvan
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Joined Jun 17, 2018
13 Posts
We are typically running about 7500 lbs GVW in Chicago traffic and also 100 mile runs on the highway. The little motor launches the van quite well, since it has way more bottom end than typical gas v-8's (325 ft lbs @ 1500 rpm, 370 @2000).
This van runs a Turbocharged 2.8 Diesel that makes 360FtLbs @ 2000 and 185 HP @ 3200RPMs, and a 8 speed automatic.
In the city, it drives about the same as the 5.4 E 250 it replaced. On the highway, no trouble merging and accelerating while loaded. It’s no race car, but it’s fine.
Fuel Economy is exceptional when heavily loaded. We run about 20 to 21 mpg city, and holding a steady 66 mph (at 65 it will downshift to 7th) we just got 33.3 mpg in humid 90 weather with A/C on over 60 miles. On open road without trailing a semi, we get a little over 30.
The other one is a 2019 Chevy Express Passenger RWD 3500 155” wheel base custom outfitted running 4.3L V6 with Direct Injection and variable Valve Timing making 298ft-lbs@3,900rpm, and 276hp @ 5,200rpm though a 8 speed automatic.
This large buzz bomb can make 19 City and 29 Highway MPG.
REALLY!
The diesel is closes to my plans for my 383.
Here is the latest update on the van engine build.
The Engine is all figured out and built.
The current question is how to feed her. What kind of intake will work best, especially at my projected low 1500 to 2000RPM operating speeds.
Ever sense I discovered the 3Rd. Gen Camaro site I was sure I wanted to run a TPI intake.
This idea came into question with my switching from a 350 to a 383 and because nearly everyone felt that the TPI was made to work best any 2800 RPMs and that it would not work with my 1500/2000RPMs.
So many were so sure of this “FACT” I was persuaded to buy and plan on using the Van’s TBI on an adapter.
It took some time for a thought to work its self up to the forefront: OMG everyone is saying a TPI peaks at 2800RPMs….SO DOES an standard Cam used in these cars!!!
It’s NOT the intake it’s the cam….
So a new research was done and I found Ken Schueneman at FIRST Performance LLC a person whom REALLY knows the TPI intakes. And he agreed with my findings of the cam making the Torque Peak at 2800RPMs not the intake.
So I had a long talk with Ken, we concluded that with my main interest is LOW RPM operation and plan of gearing my van to run between 1500 and 2000 at highway speeds like 70 to 85MPH and my hope and belief that doing such will very likely to give me 20MPG Plus and PERHAPS even reach 30MPG on level roads with no wind.
I am very much aware in other conitions I will not get those MPG, BUT then I will have the power to clime those mountians at any speed I want to run, and if slowed down be able to regain that speed again thanks to having the real power a large engine gives. I believe it is know as power to wheight ratio.
Taking how my engine is built, the specs allow all the above and that everything does indeed lean towards making my goals happen and all of this: the 193 Stock heads, the cam, the crank and rods, my engine will almost never run over 5000RPMs.
Ken said that a stock TPI system will match my engine very well. It will majorly improve its performance over the performer intake.
Now the major questions are what PCM: Do I modify my current Vans PCM to run the injectors as a dual batch injection system…and do I really need the Dynamic EFI add in board or can I reach my tuning goals the old fashion way with a Tunercat and have chips burned….?
OR run a second PCM more suited to allow better tuning and run the van’s PCM piggy back to operate the 4L60E transmission?
After all I have read and Ken has done we concluded how the fuel is fed to the engine, either TBI, 87 TPI all at once, later dual batched (4 +4) or even sequential has shown very little difference in MPG, Ken has seen the most improvements with tight ING timing.
He has not done any work with Lean Burn Highway Modes and was not a fan of my idea of using EGR to help maximize MPG but we did agree I will most likely get the best use of EGR with his external EGR add on system and to close off the factory system.
One last question will be MAF VS MAP. This will depend on the fuel system’s PCM. I have long leaned towards MAF but it can be a bit harder to install and sadly the older MAF sensors seem to have a poor history. My research has shown MAF is a little more sensitive to engine running…
It is nice to at last be able to use parts I bought around the year of 2000 and to finish an engine I started in 2005.
The Research continues….
Today
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